There are many devices sold with the purpose of exercising abdominal and other muscle groups. However, previous devices have been large and costly.
Additionally, previous exercise devices are not as effective as possible because they lack adjustable resistance. Adjustable resistance is a key element in successful strength training. Without adjustable resistance, each individual operator cannot vary his or her use to specific physical conditions. Moreover, previous devices that utilize springs do not provide adequate resistance in both the compression and expansion stages of operation.
Other problems with existing exercise devices include difficulty of use and discomfort during operation. Back problems are especially problematic during abdominal exercise because of the stress placed on the lower spine. Many devices on the market today inadvertently target other muscle groups, such as hip flexures, and not the abdominal muscles.
Needs exist for improved exercise devices that target specific muscle groups, have readily adjustable resistance settings, and are safe and comfortable during operation.